Improvement in steam-generators



s. WILCOX, Jr. STEAM GENERATOR.

No. 51,395. Patented Dec. 5, 1865.

VIJ

UNITED STATES PATENT OFFICE.

STEPHEN WILCOX, JR., OF VVESTERLY,'RHODE ISLAND, ASSIGNOR TO HIMSELF ANDCHARLES POTTER, JR., OF SAME PLACE. l

IMPROVEMENT lN STEAM-GENERATORS.

Specification forming part of Letters Patent No. 51,395, dated December5, 1865.

Similar letters of reference indicate like parts in all the figures. l

My boiler is upright. The heating-surface is formed almost entirely oftubes; but an ani-l ple surface for the disengagement of the steam isprovided at the water-level, and a proper space is also provided for thedeposit of mudl at the bottom. These, as also many other important ends,are fulfilled more perfectly in my boiler than in any other of analogouscharacter known to me.

To enable others skilled in the art to make and use my invention, I willproceed te describe its construction and operation by the aid of thedrawings and of the letters of reference marked thereon.

A is an upper lor main chamber, of cylindrical form, and traversed nearthe axis by the tubes B, which serve as drying and superheatling tubes.The lower plate, A', of the chamber A is tapped to receive two circularrows of Screw-thimbles, C, which thimbles are tapped on their interiorsand receive the screwed ends of tubes D in the manner represented. Thelower ends of the tubes D are screwed into the upper plate, E', of anannular lower chamber, E, serving as a water and Inud chamber. The fuelrest-s on the grateF, and gaseous products of combustion risingtherefrom pass upward until` they meet a horizontal plate, G, then passoutwardy between the inner set of tubes, D, andvdownward around theAouter row of tubes beneath the lower edge of. a hanging curtain, G,which is connected to the periphery ot' the plate G. The gases thenrise, having imparted a portion of their heat to form steam in the innerseries of the tubes D, and again another portion of their heat to formmi u y,

` chamber A.

steam vin the outer series of the tubes D, and

thence move inward between the plate G and the plate A' again impartingsome heat tothe tubes D, ultimately rising through the drying andsnperheating tubes B into the chf mney Il.

Bent tubes I, much smaller than the tubes D, are inserted in the mannerrepresented, one

tube I *being placed in each tube D in such manner that the lower endshall project downward beyond the lower end of D, and the. upper endproject upward beyond the upper end ofthe thimbleO, and serve as anellicient circulating-tube to `-carry a `constant and active current ofwater downward through the center of the tub'e D to supply the place ofthe water which is raporized, as aise that which is drawn upward by theascending particles of steam. The bend t' at the upper end isimportantfor iusuringthatthefluid received may be dense water, and notthe mingled steam and water which is found immediately over each thimbleO. The lower end,by projecting down= ward into the water-annulus,delivers its downward current in such a manner as not to interfere withthe upward current ascending from E into D. I propose, in some cases, tointroduce a perforated plate, as indicated by J, to allow mud to settlein the bottom of the annulus E, entirely undisturbed byany currentsdescending through the pipes I. v

The steam generated in the pipes D, as also that formed on the interiorof the annulus E and on the lower plate, A", of the chamber A,

all rises freely to the water-level, and is ulti`` A mately drawn inwardbetween the superheting-pipes B and discharged through the steampipe K,which connects to the center of the The chamber A andthe aunulus E areof Ithe same external diameter. They are incased nient along theexterior of the curtain G', and

also forms a. protection toprevent radiation of heat from the exteriorsof the chambers A and E. 1t is important for both these uses that thejacketL be a good non-conductor. Its qualities in this respect areavailable in protecting A and E from cooling by radiation, and inpreventing the external a-ir ot' the building or vessel from becominginconveniently heated and conveying away the useful heat which stillremains in the gaseous products of combustion in the intermediate spacebetween A and E.

I stop the spaces between the tubes D 1) by introducing properly-shapedcastings c, which extend from the tube-sheet E upward about half-way tothe tube-sheet A. It follows that the gaseous products ot' combustioncannot tlow directly outward from thefurnace to pass under the loweredge ot' the sheet G', but must first rise up nearly or quite to theplate Gin order to mount over these castings c. ln other words, thecastings c, arranged as described relatively to the tubes D, act as abridge, and the gases are compelled tirst to rise and pass over them andafterwards to sink and pass under thehanging bridge G. rlhis insures athorough presentation ot' the gases to thetubes D.

This boiler allows a great iluctuation rn the level ot' thewater `andwill bear an exposure of most intense heat when'such accidentallyoccurs.

The conducting -jacket L is in two halves, fitted to each, as indicatedin Fig. 2. I maintain the parts in this position by any convenientattachments, preferring,however, one acting on the principle of the haspand staple, as indicated. When dirt accumulates in the spaces betweenthe tubes D it is necessary only to remove the jacket L in order toobtain the fullest access thereto. Hand-holes covered by convenientdoors I, as indicated, allow of cleaning around the lower end of thetube without removing thejacket.

XVhen it is necessary, for any reason, to remove a tube, D, I firstremove thejacket L and then, applying a suitable wrench, turn the thitnble C in such direction as to move it downward upon the tube D untilit is entirely below the plate A. I then turn the entire tube D, so asto unscrew it from the plate E'. It is then free from both plates andmay be readily removed with its interior tube, I, and may be repaired orits place supplied by a new one by reverse operation. In ease one of thetubes in the inner series requires removal I first remove the two tubesexterior to it in order'to gain convenient access to it, and afterwardreplace the whole.

It will be seen that this boiler is easy to repair and that its luescannot become choked with ashes, so as to cause more than a very briefdelay in cleaning them.

Fire brick or other enduring material may be substituted in place ofiron plate G.

This boiler possesses the advantage of a Very high furnace. It presentsthe water to the hot gases within tubes, yet without exposing thetube-plates to an insu iierably high temperature. It circulates thewater actively, and breaks up and distributes the hot gases effectually,so as to extract the heat well from every particle.

It will be observed, of course, that the. tlat upper and lower sheets ofthe chamber A are effectively stayed by the tubes B. In making a verylarge boiler I would make the top plate ot A either in the form ot'adome or ot' a swelled ring, as indicated in red lines in Fig. l, so asthe better to enable theannular surl'ace exterior to the tubes B toresist the pressure.

It has been common to convey the water down the interior of uprighttubes to supply the place ot' the water evaporated and that carriedupward by the current of steam; but it has not before been practiced toconvey the water quite through and beyond the bottom ot' the tube and toprovide a suitable water and mud chamber, E, to perform like this.

It will bc-observed that the conical form of the interior of the annularchamber E provides fora much larger area of grate, and particularly fora larger furnace, than would be produced did the interior of E coincidein diameter with the clear space linclosed within the tubes I); but thisform of furnace is not essential, because the boiler will performsatisfactorily with the lire-grate contracted and placed within theinner row of tubes.

One very marked advantage, due to the protrusion ot' the bent top z' ofeach circulatingtube l above and beyond the top ofthe steamgeneratingtube'D, lies in its ei'ect when the water in the boiler becomes verylow. Circulating-tubes with bent tops analogous to i have been usedbefore; but in such case the generating-tubes D were extended up beyondthe end ot I, so that the bend 'i was in fact extended through a hole inthe side of the generatingl 4 tube just above the tube-sheet. Thearrangements might be identical when the water is plenty; but when thewater becomes low -my boiler will operate satisfactorily, while theforlner arrangement referred to would fail to deliver any water over thetop of the prolonged generating-tube. 'Ihese tubes end at or below theupper edge of the thimbles C, and the water carried up by the ascendingsteam spreads immediately upon the surface of the plate A. These tubes It', by reason ot' their peculiar construction, as described, allow ofrepairs kbeing more readily effected. In order to remove the tube I i itis necessary simply to raise it bodily. The tube I, bending over theupper end Ot' the generating-tube D, is out of range of the risingcurrent, and at the saine time the bend does not interfere with itsready removal, and when the water gets very low the column has only torise to a level with the crown-sheet.

The thimbles C may be rusted, soldered, or otherwise firmly fixed on thetubes D prior to the introduction into the boiler, and may in such casebe applied and removed with the tube D by turning the entire tube andits attach ments around. The part (l may be welded upon the tube D,if'preferredg butin allsuch cases the tube must be inserted and removedthrough the top of chamber A. Y

Having now fully described my invention,

what I- claim as new, and desire to secure by necting them,substantiallyin the manner and A for the purposes herein set 'orth.

3. The within-described construction and arrangement ofthe parts C G Gor their equivalents, whereby tl1e"=(lraft is made to pass first earound the middle and lower portions of the tubes Dan d' then aroundtheir upper portions, and tinally through the tubes in the steam'-ehamber, as herein set forth.'

4. The conical sides of the -'urnace F, arranged, as represented,relatively to the tubes M W W D I, and adapted to extend the furnaceout- -ward under the tubes D, substantially asherein specified.

5. ylhearrangement of the arm i, extending, laterally from the axial-line of the tube I above the tube-sheet A', and the extension of thelower end of the tube I below the tube-sheet E', substantially as hereinspecified, for the purpose of receiving` the water at the upper endunmixed with the steam rising from the tube D, and of delivering it atthe lower end without interfering with the current rising into the tubeD. K

6. The within-described arrangement ot' the steam-pipe Kwl:ereby itreceives the steam from the interior of a series ot' tubes, B, and

compels it to/circulate more perfectly in contact with the latter beforeitsexit from the boiler, substantially as herein specified.

In testimony whereof I have hereunto set my -hand in the pre-sence oftwo.subscribing witnesses.

'STEPHEN WILCOX, JR. Witnesses:

'EMIL VossNAoK,

D. W'. SrErsoN.

